[PATCH 3/4][SRU][U/L/K] thunderbolt: Increase DisplayPort Connection Manager handshake timeout

[Koba Ko]

From: Mika Westerberg <mika.westerberg at linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/2021949                                 

It turns out that when plugging in VGA cable through USB-C to VGA/DVI
dongle the Connection Manager handshake can take longer time, at least
on Intel Titan Ridge based docks such as Dell WD91TB. This leads to
following error in the dmesg:

  thunderbolt 0000:00:0d.3: 3:10: DP tunnel activation failed, aborting

and the display stays blank (because we failed to establish the tunnel).
For this reason increase the timeout to 3s.

Reported-by: Koba Ko <koba.ko at canonical.com>
Cc: stable at vger.kernel.org
Acked-By: Yehezkel Bernat <YehezkelShB at gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg at linux.intel.com>
(cherry picked from commit b6d572aeb58a5e0be86bd51ea514c4feba996cc4
git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt.git)
Signed-off-by: Koba Ko <koba.ko at canonical.com>
---
 drivers/thunderbolt/tunnel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index 45109c8c660b1..e0a79747edd5e 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -520,7 +520,7 @@ static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
 	 * Perform connection manager handshake between IN and OUT ports
 	 * before capabilities exchange can take place.
 	 */
-	ret = tb_dp_cm_handshake(in, out, 1500);
+	ret = tb_dp_cm_handshake(in, out, 3000);
 	if (ret)
 		return ret;
 
-- 
2.34.1